JP2004071151A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical disk device in which sector synchronism can be secured surely in an optical disk in which a recording track of a groove part and a recording track of groove interval part are connected alternately and one recording spiral is formed. <P>SOLUTION: Timing of a sector discriminating signal is detected from a waveform of a tracking error signal of an optical disk in which a part of a discriminating signal is arranged shifting it from the center of a groove part in one side direction of a radius by a fixed quantity and the other part of the discriminating signal is arranged shifting it from the center of the groove in the reverse direction of a radius by the same quantity, and sector synchronism can be secured based on the timing. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an optical disk apparatus that records signals on both a recording track of a concave portion formed by a guide groove and a recording track of a convex portion formed between the guide grooves.

As a recording method for a large-capacity rewritable optical disk medium, so-called recording of data in both a groove portion (also referred to as a groove: G) and an inter-groove portion (also referred to as a land: L) for improving recording density. A land / groove recording method has been proposed. Since the recording track pitch can be halved with a disk having the same groove pitch, the effect of increasing the recording density is great. The groove portion and the inter-groove portion may be referred to as a concave portion and a convex portion, respectively, depending on their shapes.
As a conventional land / groove recording optical disk, for example, there is one described in Japanese Patent Application Laid-Open No. 63-57859 as shown in FIG. As shown in FIG. 13, a groove portion 94 and a land portion 95 are formed by a guide groove cut on the disk substrate, and a recording film 91 is formed thereon. The recording pits 92 are recorded on both the recording film of the groove 94 and the land 95. On the disk, the groove portions 94 and the land portions 95 form continuous recording tracks. The focused spot 93 of the optical disk device for recording and reproducing the recording medium records / reproduces information while scanning either recording track. In the conventional land / groove recording format, since the guide grooves are continuous on the disk, the recording tracks are continuous in both the groove portion 94 and the land portion 95, and each of them forms a continuous recording spiral. .

Next, the single spiral land / groove format will be described. FIG. 14 shows a recording track of a groove (hereinafter, also referred to as a groove track) corresponding to one round of the disk and a recording track (hereinafter, also referred to as a land track) of a groove provided between the grooves, which also corresponds to one round of the disk. 3) is a diagram showing a configuration of an optical disk having a format in which one recording spiral is formed by alternately connecting recording spirals. As an optical disk having a format in which a recording track of a groove portion and a recording track of the inter-groove portion are alternately connected as shown in FIG. 14 to form one recording spiral, for example, JP-A-4-38633 and There is one described in JP-A-6-274896. Such an optical disk format is herein referred to as a single spiral land / groove format or SS-L / G format.
The SS-L / G format disk has a great feature that it is suitable for continuous recording and reproduction of data because recording tracks are continuous on the disk. For example, in video file applications, continuous recording and reproduction of data is essential. However, in the conventional land / groove recording as shown in FIG. 13, since the land track and the groove track each constitute one recording spiral, for example, when recording and reproduction are continuously performed from the land track to the groove track. Continuous recording / reproduction is interrupted by an access connecting between a land track and a groove track in at least one position on one surface of the disk. This is the same when recording and reproduction are continuously performed from the groove track to the land track. In order to avoid such interruption of recording and reproduction, it is necessary to add a buffer memory, which is a cost increase factor. However, if a single spiral land / groove format is used, this becomes unnecessary.
On the other hand, in the SS-L / G format, the polarity of the tracking servo must be switched once for one round of the disk, and it is difficult to detect the switching point, so that it is difficult to apply the tracking servo. did not exist. In fact, Japanese Patent Application Laid-Open Nos. 4-38633 and 6-274896 also disclose that the optical disk is in the SS-L / G format, but it does not provide a method for detecting a specific switching point. Is not disclosed.

In order to apply tracking servo to the SS-L / G format disk, a connection point connecting the recording tracks in the groove portions and the recording tracks in the inter-groove portions is accurately detected, and the tracking servo polarity is set there. It is necessary to switch the servo polarity between setting to track the recording track or setting to track the recording track in the groove. An example of a method of detecting a connection point where a recording track in a groove portion and a recording track in an inter-groove portion are alternately connected is disclosed in JP-A-6-290465 and JP-A-7-57302.
Japanese Unexamined Patent Publication No. 6-290465 discloses a method of providing irregularities of a constant frequency at a connection point between a recording track in a groove and a recording track in an inter-groove. FIG. 15 shows the configuration of an optical disk recording medium described in the publication. Here, there are connection points at A1, A2, A3, B1, B2, etc. in FIG. The groove or the groove is continuous between the connection points between the groove and the groove, and the positional information such as the track address is based on the wobbling of the groove.
Japanese Patent Application Laid-Open No. 7-57302 discloses a method in which a flat portion having no groove or a predetermined bit pattern is provided at a connection point between a recording track in a groove portion and a recording track in an inter-groove portion. FIG. 16 shows a configuration of an optical disk recording medium described in the publication. (A) is an example in which a flat portion is provided at a connection point, and (b) is an example in which a predetermined bit pattern is provided. In this conventional example, there is no disclosure regarding position information such as a track address, and it is considered that the groove or the groove is continuous between the connection points of the groove and the groove.

Now, consider a case where a recording track is composed of a plurality of recording sectors, and bit pattern information for connection point detection is added to a disk having a sector format configuration in which unique identification information is given to each recording sector. In the method of providing identification information by wobbling of the groove, there is no intermittent portion in the groove of the information recording portion, so that there is no problem of erroneous detection of a connection point. However, the function of sector recording is limited, for example, it is difficult to perform recording and reproduction in short sector units.
On the other hand, when a format is adopted in which an information recording unit for recording preformatted identification information indicating an address and the like and user data is separately arranged on a recording track, as in a conventional ISO magneto-optical disk, In addition, there is a problem that the identification information and the connection point of the groove / groove portion are erroneously detected as being represented in the same recording form. To avoid this, it is necessary to be able to reliably identify the identification information and the bit pattern for detecting the connection point between the groove and the groove. In the example disclosed in Japanese Patent Application Laid-Open No. 7-57302, there is no place where the pit row enters as shown in FIG. However, when the identification information to be pre-formatted is arranged in the recording track in the same pit string pattern as the bit pattern for connection point detection, accurate bit synchronization is required to detect the connection point with accurate bit synchronization. It is necessary to reproduce the information. This is common to the case where a connection point is detected based on a bit pattern, regardless of how the connection point is represented as a pattern of a fixed frequency or a predetermined pattern.
To reproduce bit information with accurate bit synchronization, it is assumed that stable tracking has been established, that is, the connection point between the groove and the groove is accurately detected and the tracking is switched. The premise of this is that, for that purpose, it is necessary to take accurate bit synchronization and play back while discriminating the bit pattern for connection point detection and the identification information accurately. Become. This is because, in the conventional optical disc alone, a single spiral land / groove is used for an optical disc of a format in which a recording track is composed of a plurality of sectors and a preformatted identification information and an information recording section are separately arranged. This indicates that it is difficult to stably detect a connection point between the groove and the groove, which is essential for realizing the recording format.

Now, a description will be given of a method of inserting an identification signal prepit proposed in a conventional land / groove recording type optical disk. In a conventional land / groove recording method that is not a single spiral, there are three known methods of inserting an identification signal prepit as shown in FIG. In the method shown in FIG. 17A, which is also called a land / groove independent address method, a unique sector address is assigned to each of the land track sector and the groove track sector. If the pit width representing the identification signal is made the same as the groove width, the identification signal pre-pits of the adjacent track sectors are connected, and the signal cannot be detected. Therefore, the pit width of the identification signal is smaller than the groove width. , About half of the groove width.
However, at this time, unless the beam diameter of the beam for cutting the pre-pits and the beam for cutting the grooves are changed in the optical disc master making process, the grooves and the pre-pits having different widths cannot be continuously formed. Therefore, it is necessary to perform cutting of the master using two beams, a beam for groove cutting and a beam for pit cutting. If the centers of the two beams are shifted, a tracking offset occurs during reproduction of the identification signal pre-pit and during recording / reproduction of the information recording signal, thereby deteriorating the quality of reproduced data. Specifically, the error rate increases due to the deviation of the tracking, and the reliability of the data decreases. For this reason, high accuracy is required for the alignment of the two beams, which causes a cost increase in the process of manufacturing the master disk.

In consideration of such circumstances, the method shown in FIG. 17B or FIG. 17C in which the groove and the pit can be cut by one beam is preferable from the viewpoint of the accuracy of the disk production and the cost. FIGS. 17B and 17C show a method of adding an identification signal pre-pit that can make the groove width and the pre-pit width substantially equal.
FIG. 17B shows a conventional optical disk described in JP-A-6-176404, which is also called a land / groove shared address system. This is a method in which prepits for identification signals are arranged near the center of a pair of adjacent groove tracks and land tracks, and the same identification signal prepits are shared by both tracks.
FIG. 17C shows a conventional optical disk described in Japanese Patent Application Laid-Open No. 5-282705, which is a time-division L / G independent address system. An independent address is added to each of the land track and groove track, provided that the positions of the pre-pits are shifted in a direction parallel to the tracks so that the pre-pits of the identification signal do not adjoin on adjacent tracks. It is.

Another point to consider when considering a method of adding an identification signal and information for detecting a connection point is resistance to defects. When switching the tracking polarity by reading the identification signal or the information for detecting the connection point, the determination should not be erroneous due to a slight defect on the medium, and the groove and the groove should not be mistaken. It is important not to erroneously detect a connection point with respect to a typical medium defect such as a fine scratch on a medium, a defective hole having a hole in a medium film and a decrease in reflectance.

Further, when considering a method of adding an identification signal and information for detecting a connection point, consideration for the servo characteristics is required in connection with the method.
In the SS-L / G format, recording is performed on both lands and grooves, so that the track density is high. For this reason, if the tracking offset becomes large, the reproduction signal quality is degraded due to crosstalk from an adjacent track, for example, an error rate is increased due to an increase in jitter, and a cross erase in which a part of the adjacent track is erased during recording occurs. Or Since the error causing the tracking offset is generated in a combined manner in the optical head system, the track arrangement on the disk, and the servo circuit system, it generally occurs in the land track and the groove track in different sizes.
In order to avoid crosstalk and cross-erase, it is necessary to perform offset compensation of different magnitudes for each track of land and groove. In the conventional land / groove method, that is, in a method in which one recording spiral is constituted by each of the groove track and the land track only, each land / groove track is recorded while each track is continuously tracked. The corresponding offset compensation was performed for a certain period of time, and the compensation amount was maintained after the adjustment, so that the offset compensation could be easily performed.

However, in the SS-L / G format disk, the switching of the tracking polarity between the land track and the groove track must be performed at a high frequency of once per rotation of the disk. Therefore, it is necessary to accurately perform the tracking offset compensation in a short time. Sex comes out. As described above, in the SS-L / G format, a method of adding an identification signal in consideration of tracking offset compensation is required.

In the above-described conventional method of inserting the identification signal into the land / groove recording, the method required for the SS-L / G format disk to cope with such a medium defect and to compensate for the tracking offset is required. I couldn't do that.
For example, in the case of the land / groove shared address system shown in FIG. 17B, during reproduction of the identification signal, the pits are on only one side, so that the tracking offset is increasing. In the case of the L / G independent address system as shown in FIG. 17C, the same applies to the case of FIG. 17B, but it is difficult to detect the tracking offset.

Next, points related to the drive operation of the optical disk will be described. Quick and accurate detection of the connection point between the groove and the groove becomes even more difficult when a control method is used in which the number of rotations of the disk changes while the optical disk is being driven. However, such a control method is mainly applied to an optical disk which is mainly used for video applications where continuous recording and reproduction of data is essential. The situation will be explained.
When importance is placed on compatibility with a read-only optical disc in a rewritable optical disc, a phase change medium in which an optical system is easily shared with a read-only optical disc is suitable as a recording medium. However, a phase change medium having recording / reproducing performance that can be put to practical use at present has a narrow range of recording linear velocities that can satisfy recording / reproducing characteristics when performing PWM recording. Specifically, when the disk rotation is controlled by CAV (Constant Angular Velocity), the disk rotation speed at the inner circumference and the disk rotation speed at the outer circumference are the same, and the recording linear velocity is 2.5 times larger than the inner circumference at the outer circumference. Up to about three times faster. It is difficult for current media to cope with such a wide recording linear velocity.
When the disk rotation is controlled by CAV, if the required data rate is fixed at the inner circumference to a required number of rotations, the outer circumference requires high-speed processing of the signal processing circuit system nearly three times the inner circumference, realizing low-cost hardware. Is difficult. Also, considering video applications, it is desirable that the data rate be constant at the inner and outer circumferences of the optical disc.
Therefore, in a rewritable optical disk for digital video recording use, a zoned constant linear velocity (ZCLV), that is, the optical disk is divided into a plurality of zones in the radial direction and the disk rotation speed is determined by the zone characteristic and the circuit performance for two reasons. In this case, the transfer rate is constant in all zones, and the linear velocity is almost constant.
The problem here is that ZCLV requires the disk rotation speed to be switched when passing through a zone boundary, and when moving from one zone to another, the disk rotation speed is settled to the specified rotation speed of the newly shifted zone ( (Settling time) until it becomes stable, and because the sector interval fluctuates during this period, it is highly likely that the sector synchronization is temporarily lost, and it is necessary to quickly re-establish the sector synchronization. is there. At the same time, it is necessary to quickly and accurately detect the connection point between the land track and the groove track.

(4) Further, a conventional land / groove recording type optical disk device will be described. FIG. 18 is a block diagram showing a configuration of a conventional optical disk device described in Japanese Patent Application Laid-Open No. 6-176404. In FIG. 18, reference numeral 100 denotes an optical disk, 101 denotes a semiconductor laser, 102 denotes a collimating lens for converting the laser light from the semiconductor laser 101 into parallel light, 103 denotes a half mirror, and 104 denotes the parallel light passing through the half mirror 103 on the optical disk. An objective lens 105 for emitting light is a photodetector for receiving the reflected light from the optical disc 100 that has passed through the objective lens 104 and the half mirror 103, and divided into two parts in parallel with the track direction of the disc to obtain a tracking error signal. And two light receiving sections. Reference numeral 106 denotes an actuator for supporting the objective lens 104, and the portion 107 surrounded by the dotted line is attached to the head base, thereby forming an optical head. Reference numeral 108 denotes a differential amplifier to which a detection signal output from the photodetector 105 is input. Reference numeral 109 denotes a tracking error signal from the differential amplifier 108, and a control signal T1 from a system control unit described later. This is a polarity inversion unit that outputs a tracking error signal. Here, as for the polarity of the tracking control, when the tracking error signal is input from the differential amplifier 108 to the tracking control unit 110 with the same polarity, the tracking pull-in is performed on the recording track of the groove. Reference numeral 110 denotes a tracking control unit that receives an output signal from the polarity inversion unit 109 and a control signal T2 from a system control unit 121 described below and outputs a tracking control signal to a driving unit 120 and a traverse control unit 116 described below. Reference numeral 111 denotes an addition amplifier that receives a detection signal output from the photodetector 105 and outputs a sum signal. Reference numeral 112 denotes a high-frequency component input from the addition amplifier 111 and converts a digital signal into a reproduction signal processing unit 113 and an address reproduction unit 114 described later. And a reproduction signal processing unit 113 for outputting reproduction data to an output terminal. An address reproducing unit 114 receives a digital signal from the waveform shaping unit and outputs an address signal to an address calculating unit 115 described later. 115 receives an address signal from the address reproducing unit 114 and a control signal T1 from the system control unit 121. , An address calculating unit that outputs an accurate address signal to the system control unit 121. Reference numeral 116 denotes a traverse control unit that outputs a drive current to a traverse motor 117 described below in response to a control signal T3 from a system control unit 121 described later. Reference numeral 117 denotes a traverse motor that moves the optical head 107 in the radial direction of the optical disc 100. A recording signal processing unit 118 receives recording data and outputs a recording signal to a laser (LD) driving unit 119 described later. A control signal T4 is output from a system control unit 121 described below. And a laser drive unit for inputting a drive current to the semiconductor laser 101. A driving unit 120 outputs a driving current to the actuator 106. 121 outputs control signals T1 to T4 to the tracking control unit 110, the traverse control unit 116, the address calculation unit 115, the polarity inversion unit 109, the recording signal processing unit 118, and the LD drive unit, and inputs an address signal from the address calculation unit 115. This is the system control section.

(4) The operation of the conventional optical disk device configured as described above will be described with reference to FIG. The laser light output from the semiconductor laser 101 is converted into parallel light by a collimating lens 102, passes through a beam splitter 103, and is converged on an optical disk 100 by an objective lens 104. The laser beam reflected by the optical disc 100 has information of a recording track, and is guided to a photodetector 105 by a beam splitter 103 via an objective lens 104. The photodetector 105 converts a change in the light amount distribution of the incident light beam into an electric signal, and outputs the electric signal to the differential amplifier 108 and the addition amplifier 111, respectively. The differential amplifier 108 performs a current-to-voltage conversion (IV conversion) of each input current, obtains a difference, and outputs the difference as a push-pull signal. The polarity inverting unit 109 recognizes the track or land accessed by the control signal T1 from the system control unit, and inverts the polarity only when the track is a land, for example. The tracking control unit 110 outputs a tracking control signal to the driving unit 120 according to the level of the input tracking error signal, and the driving unit 120 supplies a driving current to the actuator 106 according to the signal to record the objective lens 104. Control the position across the track. This allows the light spot to scan the track correctly. On the other hand, the addition amplifier 111 performs current-to-voltage conversion (IV conversion) on the output current of the light receiving unit 105, adds the current, and outputs the result to the waveform shaping circuit 112 as a sum signal. The waveform shaping circuit 112 slices the data signal and the address signal of the analog waveform by a predetermined threshold value to form a pulse waveform, and outputs the pulse waveform to the reproduction signal processing unit 113 and the address reproduction unit 114. The reproduction signal processing unit 113 demodulates the input digital data signal, and thereafter performs processing such as error correction and outputs the reproduced data. The address reproducing unit 114 demodulates the input digital address signal and outputs it to the address calculating unit 115 as position information on the disk. The address calculation unit 115 calculates the address of the sector being accessed based on the address signal read from the optical disc 100 and the land / groove signal from the system control unit 121. The calculation method will be described later. The system control unit 121 determines whether the current light beam is at a desired address based on the address signal. The traverse control unit 116 outputs a drive current to the traverse motor 117 in response to the control signal T3 from the system control unit 121 when moving the optical head, and moves the optical head 107 to a target track. At this time, the tracking control unit 110 also temporarily suspends the tracking servo by the control signal T2 from the system control unit 121. During normal reproduction, the traverse motor 117 is driven in accordance with the tracking error signal input from the tracking control unit 110, and the optical head 107 is gradually moved in the radial direction along with the progress of reproduction. The recording signal processing unit 118 adds an error correction code or the like to the recording data input at the time of recording and outputs the recording data to the LD driving unit 119 as an encoded recording signal. When the system control unit 121 sets the LD driving unit 119 to the recording mode by the control signal T4, the LD driving circuit 119 modulates the driving current applied to the semiconductor laser 101 according to the recording signal. As a result, the intensity of the light spot irradiated on the optical disc 100 changes according to the recording signal, and recording pits are formed. On the other hand, at the time of reproduction, the LD drive section 119 is set to the reproduction mode by the control signal T4, and controls the drive current so that the semiconductor laser 101 emits light at a constant intensity. This makes it possible to detect recording pits and pre-pits on the recording track.

In such a conventional optical disk device, the identification signal is reproduced as a sum signal based on the signal processed by the waveform shaping circuit 112. Even when an SS-L / G format disc is played, the connection point between the land track and the groove track is also reproduced as a sum signal based on the signal processed by the waveform shaping circuit 112. Therefore, in order to accurately detect a connection point with high reliability, it is necessary to set at least an identification signal representing address information and the like and a bit pattern for connection point detection as quite different.
Even if the data or address is not ready for reproduction immediately after the tracking pull-in, the connection point must be detected. Therefore, the bit pattern for detecting the connection point must be reproducible even in an out-of-synchronization state. For this purpose, usually, a long bit number is allocated, and a prepit having a bit pattern of a low frequency, that is, a long pit is provided. It is not advisable to assign long bits to such a pattern in a large-capacity optical disk in which the redundancy is reduced as much as possible to improve the effective recording density.

Since the conventional land / groove recording optical disk medium and optical disk apparatus are configured as described above, if the identification signal adding method is applied to the single spiral land / groove recording format as it is, the connection between the land track and the groove track is not possible. There is a problem that it is difficult to accurately detect points with high reliability.
In addition, if the connection point is separated from the identification signal into a bit pattern that can be easily detected, a long number of bits is required, and there is a problem that the effective recording density is reduced.

(5) In the single spiral land / groove recording format, it is necessary to accurately perform tracking offset compensation in a short time, but there is a problem that it is difficult to detect the tracking offset.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and in a single spiral land / groove format optical disk, a connection point between a land track and a groove track can be easily formed without lowering the effective recording density. It is another object of the present invention to provide an optical disk drive for driving an optical disk medium capable of detecting and reliably switching the polarity of a tracking servo and accurately performing tracking offset compensation in a short time.

Also, when the single spiral land / groove format is applied to the ZCLV system in which the number of disk revolutions and the number of sectors change in a zone and the ZCAV system in which the number of sectors and the data frequency change according to a zone, the sector synchronization after passing through a zone boundary is performed. It is an object of the present invention to provide an optical disk drive for driving an optical disk medium that can be quickly re-established and whose access speed can be improved.

The optical disk device according to claim 1, wherein both the groove formed in the circumference on the disk and an inter-groove between the grooves are information recording portions, and the information recording portion is locally optically illuminated by light beam irradiation. An information signal is recorded by causing a constant change or a physical shape change, and the recording track of the groove portion corresponding to one round of the disk medium and the recording track of the inter-groove portion corresponding to one round of the disk medium are alternated. The recording track is composed of an integral number of recording sectors having the same length, and a leading portion of each of the recording sectors is an identification representing address information. An identification signal portion including a signal is arranged so as to be aligned on the same radius as an identification signal portion of an adjacent recording sector, and the identification signal portion includes a first portion and a second portion. The first portion is displaced by a fixed amount in one radial direction from the center of the groove or the inter-groove portion, and the second portion is displaced in the other radial direction from the center of the groove or the inter-groove portion. An optical head having a photodetector including a light receiving surface divided into two, in an optical disc device for recording information on an optical disc medium arranged to be displaced by the same amount as the fixed amount, or for reproducing the recorded information, A difference signal waveform shaping section for generating a binary difference signal from the difference signal of the photodetector; and a reproduction difference signal processing section for outputting an identification signal gate signal corresponding to the identification signal section from the binary difference signal. Wherein when recording or reproducing the optical disc medium, the timing of a recording sector identification signal is detected from the waveform of the binary difference signal, and sector synchronization is ensured based on the detected timing. To.

The optical disk device according to claim 2, wherein both the groove formed circumferentially on the disk and the space between the grooves are information recording portions, and the information recording portion is locally optically illuminated by light beam irradiation. An information signal is recorded by causing a constant change or a physical shape change, and the recording track of the groove portion corresponding to one round of the disk medium and the recording track of the inter-groove portion corresponding to one round of the disk medium are alternated. The recording track is composed of an integral number of recording sectors having the same length, and a leading portion of each of the recording sectors is an identification representing address information. An identification signal portion including a signal is arranged so as to be aligned on the same radius as an identification signal portion of an adjacent recording sector, and the identification signal portion includes a first portion and a second portion. The first portion is displaced by a fixed amount in one radial direction from the center of the groove or the inter-groove portion, and the second portion is displaced in the other radial direction from the center of the groove or the inter-groove portion. An optical head having a photodetector including a light receiving surface divided into two, in an optical disc device for recording information on an optical disc medium arranged to be displaced by the same amount as the fixed amount, or for reproducing the recorded information, A difference signal waveform shaping section for generating a binary difference signal from the difference signal of the photodetector; and a reproduction difference signal processing section for outputting an identification signal gate signal corresponding to the identification signal section from the binary difference signal. And the timing of appearance of the identification signal of the next recording sector is estimated from the waveform of the binary difference signal when recording or reproducing the optical disk medium.

の Since the present invention is configured as described above, it has the following effects.

In the optical disk device according to the first aspect of the present invention, the detection of the sector synchronization is made quicker, more accurate, and easier for the optical disk of the single spiral land / groove recording, so that the land track and the groove track can be connected. Points can be detected reliably and easily.
In the ZCLV system in which the number of disk rotations and the number of sectors change in each zone, sector synchronization after passing through the zone boundary can be quickly re-established, so that the effect is remarkable and the access speed can be improved. Even in the ZCAV system in which the number of sectors and the data frequency vary depending on the zone, the sector synchronization after passing through the zone boundary can be quickly re-established, so that the effect is remarkable and the access speed can be improved.

In the optical disk device according to the second aspect of the present invention, it is possible to estimate the time from the detection of the identification signal of one sector to the identification signal of the next sector for an optical disk of single spiral land / groove recording. become.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
Embodiment 1 FIG.
The present embodiment relates to an optical disk medium of a single spiral land / groove recording (SS-L / G) format. In this embodiment, the optical disk medium is described as being divided into a plurality of zones by a circumferential boundary.

FIG. 1 is a diagram showing a track layout of the optical disc medium according to the first embodiment of the present invention, showing the arrangement of tracks and recording sectors in one zone and the configuration of recording sectors. As shown in the drawing, tracks (groove tracks) of grooves (grooves and recesses) and tracks (land tracks) of lands and protrusions between grooves are alternately connected once for each rotation of the disk, and one recording is performed. A spiral (spiral (spiral) recording track) is formed. Here, it is assumed that the width of the groove portion is equal to the width of the inter-groove portion. That is, the groove width and the width between the grooves are equal to the track pitch, and are set to の of the groove interval.

One recording track is composed of an integer number of recording sectors, here, for example, 12 sectors, and a preformatted identification signal section (identification signal area) is added to the head of each sector. ing. The difference from the conventional example is that the land track and the groove track are intermittent at the pre-pits of the identification signal part, in other words, they are connected via the pre-pits of the identification signal part. Holds (includes) the identification information for identifying the sector and also holds (includes) the information for detecting the connection point of the groove track and the track between the grooves. The recording sector forming the recording track includes an identification signal section preformatted at the head thereof and an information recording section capable of recording user data and various management information.

FIG. 2 is a schematic diagram for explaining the arrangement of pre-pits and their address values in the identification signal portion in the recording sector of the optical disc medium according to the first embodiment of the present invention. The identification signal portion includes two portions, a front portion and a rear portion, as viewed in the scanning direction, and the front portion is displaced from the groove toward the outer peripheral side by の of the groove width. The rear portion is displaced from the groove portion to the inner peripheral side by の of the groove width.

Next, a method of adding identification information such as a sector address in the identification signal section will be described. The address of the groove (indicated as a recess in the figure) is the identification signal part immediately before the information recording part, the front identification signal part of the groove part displaced from the center of the groove to the outer periphery by half the groove width. To be added. The address of the inter-groove portion (shown as a convex portion in the figure) is recorded in the identification signal portion immediately before the information recording portion of one of the recording tracks on the outer peripheral side of the recording track of the inter-groove portion. Is added to the rear identification signal portion which is displaced to the inner peripheral side by の of the groove width. As a result, the address of the inter-groove portion is included in the identification signal portion immediately before the information recording portion in the rear identification signal portion of the groove portion which is displaced from the center of the inter-groove portion by 1/2 of the groove width toward the outer peripheral side. It becomes the added form. As described above, the address of the inter-groove portion is not the inter-groove portion, but is added to the groove portion, and the identification signal portion in the inter-groove portion does not include the identification signal.

(4) The identification signal section holds (includes) not only the sector identification information but also the sector address as well as information on the respective tracking polarities of the sectors in each of the grooves and the grooves.

This is because the tracking offset generated when cutting the master disc is taken into account when cutting the address of the groove and the address of the groove at the same time when cutting the recording track of the groove. From the tracking offset characteristics, if the tracking offset is smaller when cutting the groove address when cutting the recording track in the groove and cutting the address in the groove when cutting the recording track in the groove, separate them. You just need to cut.

The reason why the identification signal is displaced from the center of the track by の of the groove width is that the identification information is shared between the groove track and the track between the grooves. This is because the quality identification information can be read. If the groove width is not equal to the track pitch, the amount of displacement may be １ ／ of the track pitch.

Next, a description will be given of the addition of pre-pits and addresses in the identification signal portion at the connection portion between the land and the groove, which is aligned once in one radial direction of the disk in the radial direction of the disk. FIG. 3 is a schematic diagram for explaining the arrangement of the identification number prepits in the recording sector at the boundary between the land and the groove of the optical disc medium according to the first embodiment of the present invention and the address value thereof. In the SS-L / G format disk, there is a boundary line where the recording track of the groove portion and the recording track of the inter-groove portion are connected at one place in the radial direction. In the recording sector immediately after the connection point between the recording track in the groove and the recording track in the inter-groove portion, the arrangement of the identification signal in the identification signal portion is similar to the arrangement of the identification signal other than the boundary portion. It is displaced toward the outer peripheral side by の of the width. The rear portion is displaced from the groove portion by half the groove width toward the inner peripheral side. The address value is added to the front identification signal portion, which is displaced from the groove portion immediately before the information recording portion to the outer periphery by の of the groove width in the same manner as the portion other than the boundary portion. Further, the address of the inter-groove portion is added to the rear identification signal portion which is displaced from the inter-groove portion immediately before the information recording portion by 1/2 of the groove width toward the outer peripheral side and arranged.

In order to detect a connection point (connection portion) between the recording track in the groove portion and the recording track in the inter-groove portion, in a state where tracking is performed, in the identification signal area, the first half and the second half are inward of the track center. See which side is displaced. Regarding the address of each sector, the sector of the groove portion is the identification signal of the first half which is displaced from the groove portion to the outer periphery by だ け of the groove width, and the sector of the groove portion is only １ ／ of the groove width from the groove portion. The address can be specified from the identification signal of the latter half which is displaced to the outer periphery. In each case, the portion displaced toward the outer periphery expresses the address of the own sector, and the portion displaced toward the inner periphery expresses the address of the sector adjacent to the inner periphery of one track.

Now, here, how to detect a track connecting portion when seeking is considered. At this time, since the appearance interval of the preformat identification signal changes stepwise immediately after passing through the zone boundary, sector synchronization is easily lost. In the SS-L / G format, it is necessary to ensure that the land / groove switching point can be detected even in this case.

In the ZCLV, when seeking to a different zone, the identification signal is not detected at a predetermined time interval until the disk rotation speed is settled to the prescribed value for each zone, and the sector synchronization is lost. In such a case, with a normal L / G recording disk, tracking could be stably pulled in regardless of which land or groove track was applied. However, in the SS-L / G recording disk, if a land / groove switching point appears immediately after the tracking pull-in, tracking may be lost. Although the error occurrence probability of the tracking pull-in failure itself is low and can be recovered by retrying, it is desirable to reliably pull in the tracking even in such a case in order to improve access speed and reliability.

According to the method of adding the identification signal to the SS-L / G recording disk described in the first embodiment, the polarity can be reliably determined by the order of the direction of displacement of the identification signal as described above. Thus, it is possible to avoid such a tracking pull-in failure which tends to occur in a conventional SS-L / G recording disk.

Further, track offset correction will be described as one of other functions and effects. Optical disc standard ISO / IEC 9171-1, "130 mm Optical Disk Carriage Write Once for Information Interchange", 1990. As described above, in a sample servo type optical disk, a pair of track offset detection pits is provided at a position displaced by a fixed amount from the track center on the recording track to the left and right, and the tracking offset amount is detected and corrected. There are known ways to do this.
When the light beam passes through the middle of the track offset detection pit pair, the reproduced signal amplitude of the detection pit pair becomes equal. If the track is off-track to one side, the reproduction signal amplitude of the pit on one side increases and the reproduction signal amplitude of the pit on the other side decreases, so that the track offset amount of the light beam is detected and corrected. , So that the light beam passes through the center of the track. In the present invention, the same principle and effect can be incorporated in a single spiral land / groove recording format.

Now, it is assumed that the light beam enters the identification signal section (identification signal area) of the next groove recording sector from the information recording section (information recording area) in the specific groove recording sector. Since the head of the identification signal portion is shifted to the outer periphery of the disk by の of the groove width, a tracking error signal corresponding thereto is output. After a while, since the discrimination signal portion is shifted by 幅 of the groove width on the inner circumference of the disc, a tracking error signal corresponding to the discrimination signal portion is output. Ideally, if these two error signals are detected symmetrically, it means that the center of the track is being scanned. Therefore, by comparing the magnitude of the tracking error signal detected from the identification signal portion that is arranged at a position shifted from the inner circumference to the outer circumference, it becomes possible to control the servo around the track center.
As described above, according to the method of adding the identification signal to the SS-L / G recording disk of the present invention, it is possible to simultaneously improve the servo characteristics.

As another function and effect, resistance to a medium defect will be described. For example, in comparison with the method of adding the identification signal already described in FIG. 17B of the conventional example, in the present invention, after the difference signal is maintained at a certain high level for a certain period of time, and conversely for a certain time, the difference signal is maintained at a low level or below. Is used to represent the connection point between the land track and groove track, and to represent the identification signal of the sector, so that the signal generated by actual dust adhesion, medium defect, deterioration of the recording film, etc. There is almost no chance of erroneously detecting a change.
On the other hand, in the method of FIG. 17 (b), since the difference signal fluctuates in the same manner as that appearing in the identification signal due to the presence of only one defect, the tracking polarity may be erroneously recognized or the identification signal may not be recognized. Misunderstanding. The present invention is much more excellent in terms of resistance to medium defects.

Furthermore, another polarity discrimination method can be adopted. The identification signal contains, in addition to the address of the sector, polarity information indicating whether the sector is a land sector or a groove sector. Since identification information can be read reliably during normal tracking, it is of course possible to set the polarity according to this information.
By using the above-described method of determining the polarity based on the direction and order of displacement of the identification signal and the polarity information in the identification signal, more reliable and highly reliable setting of the tracking polarity can be realized.

As described above, the first portion, which is a part of the identification signal, is disposed with a certain amount of displacement from the center of the groove to one direction in the radial direction, for example, the outer peripheral side, and the other part of the identification signal is used. A second portion is displaced from the center of the groove in the other direction in the radial direction, that is, for example, displaced inward by the same amount as the fixed amount, and when reproducing the disc, a tracking error signal, The difference signal of the tracking sensor in the radial direction is binarized by two comparators having different thresholds, and by observing the change, the tracking polarity of each recording sector can be determined, and the connection point between the land track and the groove track can be determined. Can be reliably detected.

Embodiment 2 FIG.
This embodiment relates to an apparatus for recording and reproducing the optical disk medium described in the first embodiment. FIG. 4 is a block diagram showing a configuration of the optical disk device according to the first embodiment of the present invention. 4, reference numeral 100 denotes an optical disk, 101 denotes a semiconductor laser, 102 denotes a collimating lens, 103 denotes a half mirror, 104 denotes an objective lens, 105 denotes a photodetector, 106 denotes an actuator, 107 denotes an optical head, 108 denotes a difference signal detecting unit, and 109 denotes a difference signal detecting unit. Is a polarity inverting section, 110 is a tracking control section, 111 is an addition amplifier, 112 is a sum signal waveform shaping section, 113 is a reproduced signal processing section, 114 is an address reproducing section, 116 is a traverse control section, 117 is a traverse motor, and 118 is a traverse motor. The recording signal processing unit 119 is a laser driving unit, and 120 is a driving unit. The above is basically the same as the conventional optical disk apparatus shown in FIG. Detailed description is omitted.

The configuration of a portion different from FIG. 18 will be described. 1 is a difference signal waveform shaping section which slices an analog waveform tracking error signal from the difference signal detection section at an appropriate level and converts it into a digital value, and outputs a binarized difference signal. A reproduction difference signal processing unit that extracts the identification signal, determines the tracking polarity, and outputs a polarity detection signal to the polarity control unit 8, the polarity information reproduction unit 4, the address reproduction unit 5, and the information reproduction unit 6. A polarity control unit 8 receives a polarity detection signal from the reproduction difference signal processing unit 2 and a control signal from the system control unit, and outputs a polarity setting signal and a control hold signal to the polarity inversion unit 109 and the tracking control unit 110.
Reference numeral 3 denotes a reproduction signal processing unit which reproduces an identification signal containing address information and polarity information from a binary sum signal obtained by performing waveform processing on the sum signal, and 4 denotes a polarity indicating a sector tracking polarity from the identification signal. A polarity information reproducing unit for extracting information, an address reproducing unit 5 for reproducing sector address information from the identification signal, and an information reproducing unit 6 for reproducing user information recorded in an information recording unit on the disk. The reproduced polarity information and address information are sent to the system control unit and used for controlling the tracking polarity and the sample-hold state of the tracking control.
Numeral 7 receives information about the identification signal from the reproduction difference signal processing unit 2, the polarity information reproduction unit 4, and the address reproduction unit 5, and sends the control signal to the polarity control unit 8, the traverse control unit 116, the LD drive unit, and the recording signal processing unit 118. Is a system control unit that outputs

Next, the operation before and after the connection point between the track in the groove and the track in the groove between the optical disks will be described.
FIG. 5 shows a procedure and a method for performing tracking on the SS-L / G format disc shown in FIGS. 2 and 3. FIG. 5A shows the arrangement of the identification signals that have been pre-formatted with the grooves. The first half of the identification signal of the groove is displaced approximately 1/2 of the track pitch toward the outer periphery with respect to the groove center, and the second half is displaced approximately 1/2 of the track pitch with respect to the center of the groove toward the inner periphery. When they are arranged, the identification signal arrangements of the boundary sector portion to which the land track / groove track is connected and the normal sector portion which is not the same are different as shown in FIG. 5A, as shown in FIGS. 2 and 3, respectively.
FIGS. 5A to 5E show the operation of the tracking system / identification signal detection system when passing near the preformat identification signal of the land / groove switching sector and other normal sectors, and the mechanism of land / groove switching. . (B) is a tracking error signal, (c) is a control operation state of the tracking servo system, (d) is an identification signal detection window signal, and (e) is read data of a preformat identification signal including tracking polarity information. .
In order to explain the behavior of the tracking error signal when passing through the identification signal portion, for example, consider a light beam tracking a groove track. FIG. 5B shows a tracking error signal while the light beam is tracing the recording track, that is, a state of a difference signal of the push-pull tracking sensor.

While the light spot is passing through the identification signal portion of the normal groove sector, the first half of the identification signal portion is displaced toward the outer peripheral side. A signal indicating two-track pitch displacement, that is, a signal indicating that the tracking error signal is displaced to the maximum is obtained. Also, since the latter half of the identification signal portion is displaced inward, the tracking error signal shows that the spot is displaced by approximately 1/2 track pitch from the center of the groove to the outer periphery, ie, the first half of the tracking error signal. A signal indicating that the displacement is maximal in the opposite direction to the above is obtained.
Thus, the tracking error signal at the time of reproduction of the identification signal portion indicates that the tracking is shifted to the inner periphery in the first half of the identification signal portion, and subsequently indicates that the tracking is shifted to the outer periphery in the latter half portion. Therefore, it can be determined that the recording sector following the identification signal portion is the recording sector of the groove track. The behavior of the tracking error signal in such an identification signal section is common to sectors of any groove track.

Next, a change in a tracking error signal at a boundary where a land track changes from a groove track to a land track at a land / groove connection portion will be considered. In the identification signal portion of the land sector, the first half is displaced inward, and the second half is displaced outward. Therefore, in the tracking error signal, a tracking error signal indicating that the light spot is displaced by approximately 1/2 track pitch from the center of the groove toward the outer periphery in the first half of the identification signal portion appears, and in the second half, the spot is centered on the groove. , A tracking error signal indicating that the track is displaced by approximately 1/2 track pitch toward the inner peripheral side appears.
Thus, the tracking error signal at the time of reproduction of the identification signal portion indicates that the tracking is shifted to the outer periphery in the first half of the identification signal portion, and subsequently indicates that the tracking is shifted to the inner periphery in the latter half portion. Therefore, it can be determined that the recording sector following the identification signal portion is the recording sector of the track in the groove. The behavior of the tracking error signal in such an identification signal portion is common to sectors of any land track.
In the identification signal portion at the beginning (leading portion) of each track leading sector, the polarity change of the tracking error signal is opposite to the leading portion of the sector that has been traced up to that time. The binary error signal is obtained from the tracking error signal passing through the identification signal portion obtained in this manner by a comparator having two thresholds as shown by a dashed line in FIG. 5B. The polarity of the signal makes it possible to determine whether the sector is a land track or a groove track.

In general, the tracking servo system is designed to have a band so that it hardly responds at the length of the identification signal portion. Even if a tracking error signal is generated between the identification signal portion and the trace, the light beam is not affected. Keeps tracing the track center, that is, the side edge portion of the pit preformatted in the identification signal portion. Alternatively, as a practical method, it is also possible to sample and hold a tracking error signal immediately before the identification signal section in order to cut off extra disturbance to the tracking servo system, and to pass the identification signal section by inertia with tracking control off. . FIG. 5C shows this state.

(5) Reading of identification signal information such as a sector address is performed while sector synchronization protection is applied to an identification signal periodically appearing by an identification signal detection window signal as shown in FIG. 5D, and resynchronization is repeated each time. Furthermore, if information on the tracking polarity of the land / groove is prepared in the identification signal, land / groove switching can be performed reliably. In addition, as described above, if the tracking error signal is gated by using the identification signal detection window signal for sector synchronization protection and the error polarity is determined, land / groove switching that appears once in one round of the disk is performed. Points can be easily detected, and it is possible to improve the reliability of switching and setting of tracking polarity in SS-L / G recording.

A description will be given of a signal processing procedure in which the above-described method of detecting a land / groove track connection point is actually performed in a circuit block relating to tracking and identification signal detection in an optical disk device.
FIG. 6 shows a block configuration of the difference signal detection unit 108, the difference signal waveform shaping unit 1, and the reproduced difference signal processing unit 2. FIG. 7 shows a change in each signal during tracking of the recording track. In a differential input amplifier constituting the difference signal detection unit 108, a difference between two output signals of the two-divided photodetector 105 is obtained and output as a difference signal used for a push-pull tracking servo system.
The difference signal is binarized by the difference signal waveform shaping unit 1. At this time, in order to detect that the pre-pits are displaced to the left and right with respect to the traveling direction of the light beam by ト ラ ッ ク of the track pitch in the identification signal portion, respectively, the threshold value is set to 2 by Lth and Rth by the comparator. The level is prepared, and a binary signal L0 indicating that the tracking of the light beam is displaced to the left (inner peripheral side) with respect to the tracing direction in FIG. 7 and is indicated to be displaced to the right (outer peripheral side). A binary signal R0 is generated. If the difference signal level is equal to or higher than Lth, L0 is Hi, and if it is equal to or lower than Lth, L0 is Lo. If the difference signal level is lower than Rth, R0 is Hi, and if it is higher than Rth, R0 is Lo. The states of L0 and R0 are as shown in FIGS. 7 (c) and 7 (d). The set values of Lth and Rth are set, for example, to the level of a difference signal whose tracking shift amount corresponds to a ト ラ ッ ク track pitch. If the set value is too small, there is a risk of erroneous detection when tracking deviation occurs due to disturbance.If it is too large, the displacement of the identification signal due to the change in reflectance due to dust adhesion on the disk surface etc. Since there is a risk of overlooking it, set an appropriate value during that time. As shown in FIG. 7, the center of the amplitude of the identification signal may be used.

The binary difference signal is digitally processed by the reproduction difference signal processing unit 2, and outputs a polarity discrimination signal indicating whether the sector is a land sector or a groove sector. At the same time, a detection gate signal for estimating the appearance interval of the identification signal is also generated. As shown in FIG. 6, the circuit of the reproduction difference signal processing unit includes a delay circuit and a determination circuit.
The discrimination signal is intermittently modulated by information in the groove, and is in the form of a pit row. Therefore, the two binarized difference signals L0 and R0 are also waveforms modulated by the data signal frequency. The delay circuit monitors, for each of the two input binary difference signals L0 and R0, whether or not the pulse train obtained by reproducing the pit train continues for a certain period of time: t1 or more, and (e) and (f) in FIG. As shown in FIG. 7, when the predetermined time: t1 or more has elapsed, an L detection signal: L1 and an R detection signal: R1 are output, respectively. Each of L1 and R1 is given a pulse width t3 so that it is at least Hi between the identification signal portions. The length of t1 is set as long as possible within a range shorter than the length corresponding to the identification signal portion in view of a certain margin with respect to the linear velocity fluctuation of the disk so that it can be distinguished from other noise such as a medium defect.

In the groove sector identification signal, a pulse train continues at L0 for t1 or more, and then a pulse train continues at R0 for t1 or more. Therefore, when the first half and the second half of the identification signal are normally recognized, when R1 rises from Lo to Hi, L1 is in the Hi state. When L1 rises from Lo to Hi, R1 is still in the Lo state.
Here, L1 is latched at the rising edge of R1 to generate a signal GP as shown in (g) in FIG. 7, and R1 is latched at the rising edge of L1 to generate a signal GP as shown in (h) in FIG. Create LP. In the identification signal of the groove sector, when the first half and the second half of the identification signal are recognized, GP is in the Hi state and LP is in the Lo state.
On the other hand, in the land sector identification signal, the pulse train first follows R0 for t1 or more, and then the pulse train follows L0 for t1 or more. Therefore, when the first half and the second half of the identification signal are normally recognized, when L1 rises from Lo to Hi, R1 is already in the Hi state. When R1 rises from Lo to Hi, L1 is still in the Lo state. That is, in the identification signal of the land sector, when the first half and the second half of the identification signal are recognized, LP becomes Hi state and GP becomes Lo state. Thus, LP is a land polarity detection signal, and GP is a groove polarity detection signal. Either of these two polarity detection signals is detected from the identification signal of each recording sector.

After the time corresponding to the length of the information recording portion of the sector has elapsed after the rise of either LP or GP, the identification signal of the next sector appears. The two polarity detection signals are reset to the Lo state immediately before the identification signal of the next sector. This reset processing is performed at the rising edge of a signal represented by an identification area detection gate signal: IDG in (i) of FIG. The IDG is a signal for estimating the time from the detection of the identification signal of one sector to the identification signal of the next sector. When the polarity detection signal goes to the Hi state, the IDG is reset to the Lo state, and the IDG of the next sector is detected. Time immediately before the appearance: the state becomes Hi after elapse of t5. During tracking while reading the identification signal under normal sector synchronization, the identification signal appears during the period when the IDG is Hi, so that the noise appearing in the difference signal when the IDG is Lo is removed and the identification signal is detected. There is a function of a prediction gate signal to be performed.
In this way, during tracking, the presence of the identification signal and the direction of displacement of the identification signal are detected only by the difference signal, and whether the sector is a land sector or a groove sector can be detected based on the direction and order of the displacement. it can. According to this method, it is determined whether or not a connection point between a groove portion and a groove portion of a recording track appears for each sector, so that reliable detection can be realized.

Further, when the synchronization of the identification signal, that is, the sector synchronization is lost, the identification region detection gate signal: IDG is in the Hi state. Therefore, if the identification signal is included in the binarized signal waveform, it is clear from the above description. Thus, it is possible to quickly establish the sector synchronization by detecting the timing of the identification signal.
At this time, since the identification signal is detected by the difference signal, a signal having a large level appears in the difference signal after tracking pull-in, in a portion other than the identification signal, regardless of whether or not data is recorded in the information recording unit. Never. This can be understood from the fact that the tracking error signal is scarce during the normal operation of the tracking servo. Therefore, the feature that the identification signal can be easily detected can be recognized.

Next, the operation of the polarity control unit will be described. FIG. 8 shows the configuration of the polarity control unit 8. The polarity control unit 8 receives the polarity detection signals Gp and Lp, sends a polarity setting signal LGSET for specifying the tracking polarity to the polarity inversion unit 109, and controls the tracking control unit 110 to continue / hold the control. Has a function to send HOLD. Since a signal (TS control signal) from the system control unit is also received for the operation of turning on / off the tracking in the sequence of the device control, these are collectively determined to determine the tracking polarity and the control operation.
FIG. 8A shows a circuit block of the polarity control unit 8, and FIG. 8B shows the states of two polarity detection signals and the identification area detection gate signal IDG, and an example of setting the tracking polarity in each state. In a state where the identification signal is normally detected, when one of the polarity detection signals GP and LP is Hi, the polarity may be set to the Hi side. In other cases, it is more convenient to control the device by determining the default state, and the groove polarity is set. When the tracking polarity setting signal LGSET is Hi, the land is tracked, and when it is Lo, the groove is tracked. However, when the identification signal portion is entered, a HOLD signal is sent to the tracking control section 110 to temporarily stop the tracking control.
In FIG. 5C, the three tracking control states of land / groove / stop are represented by one signal level.

Embodiment 3 FIG.
Another embodiment of the present invention will be specifically described with reference to the drawings.
FIG. 9 shows another block configuration of the reproduction difference signal processing unit 2. The change of each signal during tracking the recording track is the same as that shown in FIG. The process from the output of the two-segment photodetector 105 to the output of the binary difference signal is the same as in FIGS. Here, as shown in FIG. 9, the reproduction difference signal processing unit 2 is composed of two blocks of a counting circuit and a determination circuit.
Since the identification signal is intermittently modulated by information in the groove and is in the form of a pit row, the two binary difference signals L0 and R0 from the difference signal waveform shaping unit 1 are also modulated by the data signal frequency. It is a waveform of a pit row. The counting circuit monitors, for each of the two input binary difference signals L0 and R0, whether or not a predetermined number or more pulses appear in the binary difference signal within a fixed time: t2 (t2> t1). , An L detection signal: L1 and an R detection signal: R1 are output. Each of L1 and R1 is given a pulse width t3 so that it becomes Hi at least during tracing of the identification signal portion. As in the example described in the second embodiment, the length of t1 is discriminated from other noises such as a medium defect within a range shorter than the length corresponding to the identification signal portion in view of a certain margin for the linear velocity fluctuation of the disk. Set as long as possible.
Since the identification signal section contains a prescribed number of preformat data defined in the format, each of the first half and the second half of the identification signal section contains a certain number or more of pulses. The identification signal can be detected on condition that at least a predetermined number of pulses are input within a prescribed time.
In the circuit shown in FIG. 9, L0 is input to the UP input of the up / down counter, a determination period t2 is applied to the DOWN input, and a clear signal for removing a noise pulse is input. Specifically, a slow clock signal may be used. In the up / down counter, in the identification signal portion, the pulse input to L0 counts up to a specified number of pulses, and outputs Hi to L1. L1 remains Hi for a time t3, and is reset by a t3 timer when t3 has elapsed. The t3 timer is a circuit that clears (resets) the up / down counter after time t3 when Hi is input from L1.
To the other up / down counter, L0 is input to the UP input of the up / down counter, a determination period t2 is given to the DOWN input, and a clear signal for removing noise pulses is input. The operation outputs R1 in the same manner as the up / down counter to which L0 is input.
Hereinafter, as in the example described in the second embodiment, the determination circuit determines L1 and R1 to generate the polarity detection signals Gp and Lp. Recognition and determination of the identification signal of the groove sector or the land sector can be performed in the same manner as in the first embodiment.

Embodiment 4 FIG.
Another embodiment of the present invention will be specifically described with reference to the drawings.
FIG. 10 shows another block configuration of the difference signal detection unit 108, the difference signal waveform shaping unit 1, and the reproduced difference signal processing unit 2. FIG. 11 shows a change in each signal during tracking of the recording track. The process from the output of the two-segment detector 105 to the output of the binarized difference signal is the same as in FIGS. As shown in FIG. 10, the reproduction difference signal processing unit 2 includes three blocks of a correction circuit, a delay circuit, and a determination circuit.
Since the identification signal is intermittently modulated by information in the groove and is in the form of a pit row, the two binary difference signals L0 and R0 from the difference signal waveform shaping unit 1 are also modulated by the data signal frequency. It is a waveform. The correction circuit uses a retriggerable mono-multi vibrator, for example, in order to detect the presence or absence of the first half and the second half of the identification signal from the two input binary difference signals. Thus, the waveform is corrected so that each of the first half and the second half of the identification signal becomes one continuous pulse. L0 is corrected to generate a binarized correction difference signal L2, and R0 is corrected to generate a binarized correction difference signal R2.
In the delay circuit, for each of the two binarized difference signals L2 and R2 input as in the example described in the first embodiment, it is monitored whether or not the pulse train obtained by reproducing the pit train continues for a certain time: t1 or more. When a predetermined time t1 or more has elapsed, an L detection signal: L3 and an R detection signal: R3 are output, respectively. Each of L3 and R3 is given a pulse width t3 so that it is at least Hi between the identification signal portions.
Hereinafter, recognition and determination of the identification signal of the groove sector or the land sector can be performed in the same manner as in the second embodiment.

Embodiment 5 FIG.
Still another embodiment of the present invention will be specifically described with reference to the drawings.
FIG. 12 shows an example in which the frequency characteristics of the difference signal detection unit 108 are limited to simplify the processing in the difference signal waveform shaping unit 1 described in the third embodiment. In the tracking control system, usually, it is sufficient to detect only the difference signal in the servo control band. Therefore, an inexpensive amplifier having a narrow band can be used as the differential input amplifier for detecting the difference signal. The discrimination signal is intermittently modulated by information in the groove, and is in the form of a pit row. In this case, the difference signal waveform is subjected to low-pass filtering as shown in FIG. It has a simplified waveform.
Hereinafter, the processing in the reproduction difference signal processing unit 2 does not require a correction circuit in the block in the third embodiment, and the binarized correction difference signal can be directly handled in the same manner as L2 and L3 in FIG. it can.
Subsequent processing is the same as in the third embodiment.

In the above-described second to fifth embodiments, the operation of mainly determining the direction and order of displacement of the identification signal from the difference signal of the tracking sensor output signal and thereby determining the tracking polarity has been described. The polarity information in the identification signal is reproduced from the sum signal of the output signals by the polarity information reproducing unit 4 and is used together with the tracking polarity discrimination result obtained from the difference signal, thereby setting a more reliable and highly reliable tracking polarity. Can be realized.

The method of detecting the identification signal and the track connection point shown in each of the above embodiments is merely an example for describing the present invention, and the same function can be realized by various circuit configurations. Needless to say, the present invention is not limited to the above embodiments.

FIG. 2 is a schematic diagram illustrating a track layout of the optical disc medium according to the first embodiment of the present invention. FIG. 3 is a schematic diagram for explaining an arrangement of identification signals in a recording sector of the optical disk medium and addresses thereof in the first embodiment of the present invention; FIG. 3 is a schematic diagram for explaining the arrangement of identification numbers in recording sectors and the addresses thereof at boundaries between lands and grooves of the optical disc medium according to the first embodiment of the present invention. FIG. 4 is a block diagram illustrating a configuration of an optical disc device according to a second embodiment of the present invention. FIG. 9 is a timing chart for explaining a method of recognizing the tracking polarity of a recording sector according to the second embodiment of the present invention. FIG. 9 is a circuit block diagram of a reproduction difference signal processing unit of the optical disc device according to the second embodiment of the present invention. FIG. 7 is a detailed timing chart for explaining a method of recognizing the tracking polarity of a recording sector according to the second embodiment of the present invention. FIG. 8 is a diagram illustrating circuit blocks and functions of a polarity control unit of the optical disc device according to the second embodiment of the present invention. FIG. 13 is a circuit block diagram of a reproduction difference signal processing unit of the optical disc device according to the third embodiment of the present invention. FIG. 14 is a circuit block diagram of a reproduction difference signal processing unit of the optical disc device according to the fourth embodiment of the present invention. FIG. 11 is a detailed timing chart for explaining a method of recognizing the tracking polarity of a recording sector according to Embodiment 4 of the present invention. FIG. 15 is a detailed timing chart for explaining a method of recognizing the tracking polarity of a recording sector according to the fifth embodiment of the present invention. FIG. 9 is a diagram showing an example of a conventional land / groove recording optical disk. FIG. 11 is a diagram showing an example of an optical disc having a conventional single spiral land / groove recording format. FIG. 11 is a diagram showing an example of land / groove connection points of a conventional single spiral land / groove recording optical disc. FIG. 10 is a diagram showing another example of a land / groove connection point of a conventional single spiral land / groove recording optical disc. FIG. 10 is a diagram showing a layout of identification signals in a conventional land / groove recording method. FIG. 11 is a block diagram illustrating a configuration of a conventional optical disc device.

Explanation of reference numerals

1) difference signal waveform shaping section, 2) reproduction difference signal processing section, 3) reproduction signal processing section, 4) polarity information reproduction section, 5) address reproduction section, 6) information reproduction section, 7) system control section, 8) polarity control section, 91) recording film, 92 recording pits, 93 condensing spots, 94 grooves, 95 lands, 100 optical disks, 101 semiconductor lasers, 102 collimating lenses, 103 half mirrors, 104 objective lenses, 105 photodetectors, 106 actuators, 107 optical heads, 108 optical differences Dynamic amplifier, 109 polarity inverting unit, 110 tracking control unit, 111 addition amplifier, 112 waveform shaping unit, 113 reproduced signal processing unit, 114 address reproducing unit, 115 address calculating unit, 116 traverse control unit, 117 traverse motor, 118 recording signal Processing unit, 119 a laser driving unit, 120 drive, 121 a system control unit.

Claims (2)

Both the groove formed circumferentially on the disk and the space between the grooves are used as an information recording portion, and a local optical constant change or a physical shape change is caused in the information recording portion by irradiation of a light beam. Thus, an information signal is recorded, and a recording track of the groove corresponding to one rotation of the disk medium and a recording track of the inter-groove portion corresponding to one rotation of the disk medium are alternately connected to form one recording spiral. In the optical disk medium formed, the recording track is composed of an integral number of recording sectors having the same length, and an identification signal portion including an identification signal representing address information is adjacent to a head of each recording sector. The identification signal portion is arranged so as to be aligned on the same radius as the identification signal portion of the recording sector, the identification signal portion includes a first portion and a second portion, and the first portion is a groove portion or an inter-groove portion. An optical disc arranged so as to be displaced by a fixed amount in one radial direction from the center, and the second portion being displaced by the same amount as the fixed amount in the other radial direction from the center of the groove or the gap between the grooves; In an optical disc device that records information on a medium or reproduces recorded information,
An optical head having a light detector including a light receiving surface divided into two,
A difference signal waveform shaping unit that generates a binary difference signal from the difference signal of the photodetector;
A reproduction difference signal processing unit that outputs an identification signal gate signal corresponding to the identification signal unit from the binary difference signal,
An optical disk device for detecting the timing of a recording sector identification signal from the waveform of the binary difference signal when recording or reproducing the optical disk medium, and ensuring sector synchronization based on the detected timing; . Both the groove formed circumferentially on the disk and the space between the grooves are used as an information recording portion, and a local optical constant change or a physical shape change is caused in the information recording portion by irradiation of a light beam. Thus, an information signal is recorded, and a recording track of the groove corresponding to one rotation of the disk medium and a recording track of the inter-groove portion corresponding to one rotation of the disk medium are alternately connected to form one recording spiral. In the optical disk medium formed, the recording track is composed of an integral number of recording sectors having the same length, and an identification signal portion including an identification signal representing address information is adjacent to a head of each recording sector. The identification signal portion is arranged so as to be aligned on the same radius as the identification signal portion of the recording sector, the identification signal portion includes a first portion and a second portion, and the first portion is a groove portion or an inter-groove portion. An optical disc arranged so as to be displaced by a fixed amount in one radial direction from the center, and the second portion being displaced by the same amount as the fixed amount in the other radial direction from the center of the groove or the gap between the grooves; In an optical disc device that records information on a medium or reproduces recorded information,
An optical head having a light detector including a light receiving surface divided into two,
A difference signal waveform shaping unit that generates a binary difference signal from the difference signal of the photodetector;
A reproduction difference signal processing unit that outputs an identification signal gate signal corresponding to the identification signal unit from the binary difference signal,
An optical disc apparatus, wherein when recording or reproducing the optical disc medium, an appearance timing of an identification signal of a next recording sector is estimated from a waveform of the binary difference signal.

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